A common method of measuring the blood pressure of a human patient involves wrapping an inflatable cuff around the patient's arm. An operator inflates the cuff thereby applying pressure to the arm. The operator then slowly deflates the cuff while measuring the blood pressure. The blood pressure may be measured by, for example, listening to blood flow using a stethoscope as the cuff is deflated. It is common for such blood pressure cuffs to be provided to a patient who must periodically monitor his or her own blood pressure at home. In such a case the patient must be trained in the proper use of the blood pressure measuring device.
Such an inflatable cuff typically includes an inflatable bladder formed, for example, of an elastic sheet such as a rubber sheet or a vinyl sheet contained within a non-stretch belt-like bag. The belt-like bag may be constructed of cloth or other material. Typically, the inflatable bladder is disposed towards one end of the belt-like bag, and extends approximately half way towards the center of the blood pressure cuff, so that a portion of the belt-like bag not surrounding the inflatable bladder may wrapped around the patient's arm to secure the cuff to the arm. The bladder may be constructed of air-tight, flexible, bio-compatible material such as PVC. Velcro.TM. patches or other connection means may be used to secure one portion of the belt-like bag to itself.
Typically the inflatable bladder is connected to an air pump which may be operated by hand to inflate the inflatable bladder. The air pump is connected to the inflatable bladder by a flexible air-tight tube or piping. The air pump is connected to a pressure sensor which provides an indication of the pressure inside the inflatable bladder, readable by a human operator. Such a pressure sensor may include a visible dial type gauge. The air pump includes a deflation-control valve device having a control such as an adjustable knob. The control may be adjusted so that the deflation-control valve allows inflation or variable amounts of deflation.
One important part of the procedure for measuring blood pressure is applying the cuff to the arm. The portion of the cuff surrounding the inflatable bladder is placed on the patient's arm, and the cuff is wrapped around the patient's arm. The cuff should be wrapped around the patient's arm with a certain amount of tension. Typically, a user will wrap the cuff, using his or her own tactile sense to gauge the amount of tension applied to the cuff, and attach a portion of the cuff to itself using, for example, Velcro patches often resulting in improper wrapping of the cuff. Improper cuff tension results in an incorrect blood pressure measurement cycle. For example, if too little tension is provided, too much air must be pumped into the bladder and the measurement cycle may be unnecessarily long, resulting in an inaccurate measurement. If too much tension is provided, the blood vessels in the arm may be compressed prior to the bladder being inflated, which instead should be controlled by the inflation of the bladder, also resulting in an inaccurate measurement.
A patient who is not a trained health professional and who is measuring his or her own blood pressure using such a device may fail to apply proper tension to such a cuff. Even health professionals using such devices may apply the cuff with inaccurate tension.
Therefore, there exists a need for a blood pressure cuff which a user may apply while being assured that the proper amount of tension is being used for placement of the cuff.